RESPONSIVENESS OF CAROTENOIDS TO A HIGH VEGETABLE DIET INTERVENTION DESIGNED TO PREVENT BREAST-CANCER RECURRENCE

Epidemiological studies suggest that a high vegetable diet may reduce risk for breast cancer and may also improve prognosis after the diagno sis of breast cancer. Circulating carotenoids may serve as a biomarker of vegetable and fruit intake, although several factors affect their bioavailability from food sources and may influence concentrations. On e purpose of this study was to identify factors predictive of serum ca rotenoid, retinol, and alpha-tocopherol concentrations in 79 postsurgi cally resected breast cancer patients at enrollment and at 12 months i n a feasibility study of a high vegetable, low fat diet intervention t o reduce risk for cancer recurrence. Another purpose was to identify v ariables associated with change in these serum concentrations 12 month s after randomization into control and intervention groups. The diet i ntervention (versus control) group had significantly greater increases in carotenoid intakes (P < 0.03) and significantly greater increases in serum concentrations of lutein, alpha- and beta-carotene, lycopene, and retinol (P < 0.04). Stepwise multiple regression revealed the lev el of dietary intake to be predictive of most serum carotenoid concent rations at baseline and 12 months, with additional associations betwee n selected micronutrient concentrations and serum cholesterol, body ma ss index, age, percentage of energy intake from fat, and alcohol intak e also observed at these time points. Intervention group change in ser um carotenoid concentrations was inversely associated with baseline le vel, age, and change in serum cholesterol concentration and positively associated with change in carotenoid and alcohol intake. Circulating carotenoid concentrations are responsive to a high vegetable diet inte rvention, which also included reduced dietary fat and increased fiber intakes, to reduce risk for breast cancer recurrence.